Shatter-pulverizing of friable solids



Aug. 2, 1955 T. NAGEL sHATTmR-PULVERIZING 0F FRIABLE soLIDs Filed Feb. 6, 1952 /I TTORNE Y United States Patent Office 2,7%,480 Patented Aug. 2, 1955 2,714,489 SHATTER-PULVERIZING OF FRIABLE SOLIDS Theodore Nagel, Brooklyn, N. Y. Application February 6, 1952, Serial No. 270,146 1 Claim. (Cl. 241--39) My invention relates to the shatter-pulverizing of friable solids wherein the solids, entrained in a gaseous service medium under pressure, are continuously ejected from a nozzle and the stream impinged against a target at very high velocity.

One of' the objects of my invention is to provide a method and apparatus for shatter-pulverizing friable solids by entraining the solids in a gaseous medium and continuously ejecting the stream from an outlet orifice and impinging the stream against a target at velocities far in excess of velocities produced prior to my invention.

inasmuch as the impact velocity produces a shatterpulverizing force which varies directly as the square of the impact velocity, I am enabled to produce impact shattering forces wh ich approximate fifty times those produced by the same pressure applied to eject streams of slurry, namely, solids entrained in liquid. i In general, the present invention provides for the shatterpulverizing of friable solids in a continuous operation by entraining the` solids in a gaseous service medium, which is under pressure, and fiowing the service medium with its entrained solids through a plurality of orifices; these orifices `are the injection and ejection orifices of a plurality of intercommunicating chambers arranged in series. The gaseous service medium, it will be understood, expands .as it enters each chamber, and I employ the critical exhaust pressure of the service medium in each chamber as service pressure to the orifice outlet of the chamber, so that the velocity of the stream of the service medium and its entrained solids will be accelerated at each ejection orifice from each chamber.

By way of illustration, if the gaseous service medium enters the rst chamber at a velocity of 39,000 feet per minute, this velocity is accelerated as the stream flows through the ejection orifice of that chamber to a velocity of the order of 67,000 feet per minute; and by employing a second chamber in series with the first, instead of discharging to the atmosphere, I am able further to accelerate the velocity of the stream as it is discharged or ejected from the ejection orifice of the second chamber to a velocity of the order of 78,000 feet per minute.

inasmuch as the impact velocity of the entrained fria ble solids, as above pointed out, produces a shatter-pulverizing force varying directly as the square of the irnpact velocity, it will be apparent that by accelerating from a velocity of 39,000 feet per minute to a velocity of the order of 78,000 feet per minute, I produce shattering forces approximating four times those produced by the initial velocity of 39,000 feet per minute and can shatterpulverize solids which heretofore could not be shatterpulverized by conventional methods.

I may add that the above-mentioned figures are illustrative rather than definitive, and that velocities even higher than those mentioned can be produced by employ ing a gaseous service medium at higher initial pressure, or by employing a service medium at higher initial pressure and owing the stream through a series-disposed third chamber.

In the accompanying drawing I have illustrated one form of apparatus which is suitable for the invention.

Fig. l is a sectional elevational View thereof; and

Fig. 2 is a section taken substantially on the line 2-2 of Fig. 1.

Referring to the drawing in detail, 2y designates the cylindrical housing of my apparatus, in the exit or discharge end of which is fitted a cylindrical plug 4.

The inner end or face of the plug 4 is provided cen trally with a frusto-conical cavity 6, and traversing the inner face or end of the plug from its periphery to the cavity 6 are a plurality of slots 8, extending radially of the plug face or end constituting feed channels.

The outlets of these slots or channels S provide an annular orifice 10, opening into the cavity 6 in the plug end. The orifice 10 for descriptive purposes will be referred to as the first injection orifice and the cavity 6 as a first chamber.

The outer end of the first chamber 6 is provided with an orifice or outlet 12 to a second chamber 14, the chambers 6 and 14 being disposed in series, and the orifice 12 not only functioning as the outlet orifice for the first chamber 6 but as an injection orifice for the second chamber 14.

The outer end of the second chamber 14 is provided with an outlet orifice 16 to atmosphere, and in front of this third orifice is a target 1S, against which the entrained solids, as they are ejected from the orice, are impinged.

The orifices 10, 12, and 16, are restricted orifices in that the area of each orifice is substantially less than that of its chamber.

Mounted within the housing 2 and resting upon the partitions 20 between the radial slots or feed channels 3 are an outer inverted cup-shaped member 22 and an inner inverted cup-shaped member 24. These members are spaced from the inner wall of the housing 2 as well as from each other.

The conduit 26, which is shown projecting through the housing 2, is a supply conduit for continuously supply ing a gaseous service medium to the apparatus. This service medium may be air, gas, or steam under pressure, taken from any suitable source of supply.

Extending through the top of the housing 2 axially thereof and through the top of the inner cup-shaped member 22 is a conduit 28. This is the supply conduit for the solids which are to be pulverized. The feed is fluidized solids, viz., solids entrained in a stream of fluid, for example, which flows continuously from any convenient pressurized source of supply.

With the apparatus in operation, the fluidized solids, as they flow continuously from the conduit 28 into the space 23 between the two members 22 and 24, will be continuously injected into the gaseous service medium, which is continuously owing through the radial practice of my channels 8 from the service supply conduit 26 and through the space 27 between the housing 2 and member 22.

The fiuidized solids are thus entrained in the gaseous service medium and will be carried by the gaseous service medium through the first injection orifice 10, provided by the feed channels 8, into the first chamber 6.

For the purposes of this description, let it be assumed that the gaseous service medium is under a pressure of 200 pounds per square inch gauge, and that the sum of the areas of the outlet ends of the radial feed channels or slots 8, constituting the first orifice, equal the area of a one-inch diameter circular orice.

Under these conditions, 212.5 cubic feet of the compressed gaseous service medium will flow per minute into the first chamber 6 at the critical ejection pressure of 99.1 pounds per square inch gauge. The ejection 3 velocity of the service medium stream flowing through the orifice 10 approximates 39,000 feet per minute.

As the gaseous service medium flows into the first chamberf, it flash-expands to its critical pressure volume of 405 c'ubic feet per minute.

From the first chamber 6, the expanded service medium stream flows through the second orifice 12 into the second 'chamber 14 at the critical gaseous exhaust pressure at this second orifice of 45.6 pounds per square inch gauge. stream flowing through the second orifice 12 is much higher, however, than 39,000 feet per minute-the velocity of the service medium fiowing through the first orifice lll-inasmuch as the gaseous service medium stream is already flowing at approximately 39,000 feet per minute, and the expansion of the gaseous service medium in the chamber 6 along with the pressure differential at the orifice 12 of 53.6 pounds per square inch gauge (the pressure in chamber 6 servicing the orifice 12 and the critical exhaust pressure at the orifice 12 e?,

of 45.6 pounds per square inch gauge) will accelerate the velocity of the fiowing gaseous medium stream from 39,000 feet per minute to a velocity of approximately 67,000 feet per minute. 405 cubic feet of the gaseous service medium ows per minute into the second chamber f 14, where it flash-expands to its critical pressure volume approximating 770 cubic feet per minute. To enable the expanded gaseous service medium to fiow from the first chamber 6 to the second chamber 14 at the accelerated velocity mentionedapproximately 67,000 feet per minutethe area of the second orifice 12 should be approximately 10% larger than the area of the first orifice 10.

yIt' this increased velocity of approximately 67,000 feet per minute is sufficiently high for shatter-pulverizing the friable solids constituting the feed material, the second chamber 14 can be omitted, so that the highvelocity gaseous medium stream with its entrained solids owing through the orifice 12 will be impinged directly against the target 18.

When, however, the second chamber 14 is employed, it will be understood that the gaseous service medium and its entrained solids exhaust from chamber 14 to the atmosphere through outlet orifice 16 at the critical gaseous exhaust pressure of approximately 17.3 pounds per square inch gauge. The expansion of the gaseous medium in the chamber 14, together with the pressure differential at the orifice 16 of 28.3 pounds per square inch gauge-the difference between the service pressure of 45,6 pounds per square inch gauge and the exhaust pressure of 17.3 pounds per square inch gauge-will further accelerate the service medium stream and its entrained solids to approximately 78,000 feet per minute. For this velocity the area of the orifice 16 should be approximately 80% larger than the area of the first orifice V10.

Thevelocity of the gaseous service medium Cil It will be seen from all of the foregoing that my invention provides for the shatter-pulverizing of friable solids by flowing a stream of solids, entrained in a compressed gaseous service medium, through a plurality of orifices, constituting the injection and ejection orifices of a plurality of chambers arranged in series. It will be appreciated that, by expanding the gaseous service medium in a chamber and using its critical exhaust pressure as additional service pressure for the ejection orifice of that chamber, the velocity of the service medium stream with its entrained solids is accelerated. It will be seen that by employing only two chambers disposed in series,

an increase in velocity up to 78,000 feet per minute can be produced. The pressures and velocities mentioned are illustrative, and it is to be clearly understood that higher velocities can be produced by employing a gaseous service medium the initial pressure of which is above the 200 pounds per square inch gauge which I have used as an illustration and by employing a third chamber disposed in series with the second chamber 14.

I wish it to be understood furthermore that the apparatus shown for the practice of my invention is illustrative rather thanV definitive, and that changes may be made therein without departing from the spirit and scope of my invention.

What I claim is:

In an apparatus for shatter-pulverizing solids, the combination of means defining a confined space or chamber, said chamber being provided with an injection orifice and with an ejection orifice; a source of supply of a compressed gaseous service medium; a source of fluidized friable solids; means for continuously conducting the compressed service medium to the said injection orifice of said chamber radially of said chamber; means for continuously conducting the uidized solids into said service medium before the latter reaches the injection orifice, the area of said ejection orifice being less than twice that of the injection orifice but at least 10% larger than that of the injection orifice; and a target adjacent the said ejection orifice against which the solids continuously discharging from thc ejection orifice are impinged to shatter-pulverize the solids.

References Cited in the file of this patent UNITED STATES PATENTS 253,344 Chichester Feb. 7, 1882 256,071 Taggart Apr. 4, 1882 767,689 Hedlund Aug. 16, 1904 1,699,441 Negro Jan. 15, 1929 2,387,548 Wiegand Oct. 23, 1945 2,392,866 Stephanoff Ian. 15, 1946 FOREIGN PATENTS 381,591 Great Britain Oct. 10, 1932 

